At least with 1.2, looking at the code, the glade files are loaded with Gtk.Builder so unless I missed something in my tests it does not need that dependency.
Also, while it would only be needed for windows platform, you could add dev-python/pycrypto[${PYTHON_USEDEP}] to dependencies.
even before glade was be wrong - it's the GUI utility for editing the XML files, not what is used to load. But yeah, looks Gtk.Builder to me (gtk+[introspection]), even though they kept the .glade extension for the files for some reason.
Thanks! Even going back to 0.3.x branch I do not find any mention of glade itself (not sure why I added it originally). Anyway dep cleaned from the ebuild, replaced by pycrypto just in case